1. Field of the Invention
The invention relates to a chute for evacuating objects distributed by a sorter conveyor; it relates more particularly to an improvement to a chute of the above kind which damps the fall of the objects and thereby prevents them being damaged and guides them better, the object being ejected flat so that, if required, objects can be stacked automatically in a receptacle extending the outlet.
The invention also relates to an object evacuation chute module including at least two chutes as defined above with outlets at different levels. Finally, it relates to any object sorting installation equipped with such chutes or modules.
2. Description of the Prior Art
A prior art installation for sorting objects groups wallets or small packets in different receptacles according to their destination. For example, an installation of the above kind is routinely used in photograph processing centers for handling wallets containing developed photographs and their negatives, to be dispatched to customers or outlets. A gripper conveyor circulates the packs along a predetermined closed loop path. The grippers travel above a plurality of evacuation chutes. Opening a gripper at a given point on its path drops the object into a selected chute and routes the object to a corresponding receptacle.
One such system is described in European patent 0 437 501, for example.
The receptacles are often sacks in which the objects accumulate loose.
Some users prefer to employ receiving hoppers and in this case, if the objects are all substantially the same shape and size, it is advantageous to orient them in the evacuation chutes so that they can be stacked in an orderly fashion in the receiving hoppers.
European patent 0 631 827 describes an arrangement of chutes which in principle enables objects to be stacked flat and in an ordered fashion in receiving hoppers at the outlets from the chutes. One chute described in the above document has a vertical part in which the object falls freely and an outlet chicane consisting of planes inclined toward each other to form a kind of elbow bend. The chicane directs the object toward the outlet at the end of its drop. The shape of a chute of the above kind in principle enables orderly stacking in a receptacle of suitable predetermined shape. Nevertheless, a certain percentage of errors occurs in stacking. In other words, from time to time, an object is not placed correctly in the stack being formed. Also, falling freely in the chute can damage a fragile object when it impacts on the chicane.
The invention proposes a new type of chute which has proved to be more effective for sorting objects of the above kind, by absorbing impacts in the chute and making orderly stacking more reliable.
More specifically, the invention provides a chute for evacuating objects distributed by a sorter conveyor, the chute having an inlet defined by a substantially horizontal opening, an outlet at a lower level than the inlet, a guide duct connecting the inlet to the outlet and having a transverse guide wall and at least one elastic deflector in the duct and having a mobile part which faces the transverse guide wall of the duct in order to push an object engaged therein momentarily toward the transverse guide wall.
By xe2x80x9ctransverse wallxe2x80x9d is meant one of the two walls of the chute which is globally transverse to the direction of movement of the object conveyed by the grippers. A chute of this kind therefore essentially has two spaced transverse walls and a back wall joining the two transverse walls.
A deflector advantageously consists of an elastic flexible blade fixed by one side to the duct and projecting downward into the duct and toward the transverse guide wall so that the elastic blade constitutes a flexible obstacle in the duct adapted to retract elastically when an object passes it and to push the object toward the transverse guide wall.
This retards the movement of the object and obliges the object to follow said transverse guide wall.
In one embodiment of the invention a guide duct of the above kind has a back wall which is globally curved in the direction of evacuation of the object. This embodiment is particularly suitable when the outlet is a very long way from the inlet.
In another embodiment of the invention a guide duct according to the invention has a back wall that is globally rectilinear in the direction of evacuation of the object. The back wall can have an upstream section merging with the transverse guide wall through a curved surface portion and a downstream section in the form of an inclined plane extending to the outlet. This embodiment is particularly suitable when the distance between the inlet and the outlet is not too great.
In both cases, the width of the duct can advantageously become greater in the upstream to downstream direction. Consequently, by combining the previous two embodiments, a module can include at least two chutes having outlets the same width at different levels. In a module of this kind two chutes are disposed side-by-side with their respective entries in the same plane in the upper part of the module and their respective outlets at different levels, one above the other.
Of course, the invention also relates to a module of the above kind and to any object sorting installation including a plurality of evacuation chutes having the features defined above or a plurality of chute modules defining at least two outlet levels.